In the related art, an image forming apparatus forms an image on a sheet with a decolorizable material, and an erasing apparatus erases an image on a sheet formed with the decolorizable material, which is decolorized when the sheet is heated to a certain temperature. By using these apparatuses, sheets can be reused so that sheets used for image forming can be conserved. One type of the image forming apparatus has a fixing unit that can fix an image onto a sheet and erase an image formed on a sheet. Conventionally, this type of image forming apparatus carries out the fixing of the image and the erasing of the image separately.